Furniture doors and construction doors can be classified into a hinged door type, a sliding door type or the like. The hinged door is a door that opens by rotating. The sliding door opens and closes by horizontally sliding on a frame composed of a head jamb and a doorsill.
In order to assist opening and closing of such a door, there is provided a door opening and closing system (for example, see Patent Literature PL1). The door opening and closing system has a catch which is mounted on either one of a door or a frame surrounding the door and a door opening and closing device which is mounted on the other of the door and the frame and cooperates with the catch.
In the door opening and closing device, a retractable arm is provided. The retractable arm is engaged with the catch. Before the door is closed, the retractable arm is in the open state. When the door gets closed, the retractable arm and the catch are engaged and the retractable arm rotates around an arm axis in the closing direction. Then, a force in the closing direction is exerted on the door. When the arm is rotated to the closed state, the door is in the closed state. On the other hand, when the door in the closed state gets open, the retractable arm rotates around the arm axis in the opening direction. When the door is opened a predetermined angle or more, engagement between the retractable arm and the catch is canceled to make the retractable arm in the open state.